My Bedroom Door Stuck Every June — Until I Found the Real Culprit

Why Wood Moves

Wood isn’t stable. It never has been, and it never will be.

Even after it’s milled, kiln-dried, finished, and hung in your doorframe, it’s still reacting to the air around it. When humidity climbs in summer, wood fibers absorb moisture from the air and swell. When dry winter air returns in fall, they release that moisture and shrink back down.

This is why my door closed perfectly in September and jammed solid every June.

Most doors are sealed on all six sides — front face, back face, top edge, bottom edge, and both long edges. That finish coat, whether it’s paint or polyurethane or lacquer, acts like a raincoat. It doesn’t make the wood completely waterproof, but it slows down how much moisture the wood can absorb, and it keeps that absorption roughly even across all surfaces.

When one side is left bare — just raw or poorly sealed wood — that surface pulls in humidity much faster than the sealed sides. The wood swells more on that unprotected edge. Since the opposite edge is sealed and stays stable, the door effectively gets thicker on one side. In a doorframe with maybe a sixteenth of an inch of clearance, it doesn’t take much swelling before the door binds.

I suspected that’s what had happened here. That whoever hung the door fifteen years ago had trimmed it to fit, gotten it plumb and latching nicely, and then skipped the final step of sealing the edge they’d just cut. Maybe they ran out of daylight. Maybe they forgot. Maybe they figured it didn’t matter because you couldn’t see that edge once the door was closed.

But I’d been paying for that shortcut every summer since, without knowing it.

The seasonal timing made sense now. June in my part of the country is when humidity really kicks in — we go from 40% relative humidity in April to 70% or higher by mid-June, and it stays that way through August. September brings cooler, drier air, and the wood gives up that moisture and shrinks back to its winter dimensions.

But I still needed to know where exactly the door was binding before I’d know for sure this was the problem — and before I’d know how to fix it.